The Legal Regime Governing the Recovery of Underwater Cultural Resources in the United States

Historic wrecks exist in many of the navigable waters of the United States, particularly along the Atlantic and Gulf coasts. Attention will mainly focus, however, on the waters off Florida. These often dangerous waters, as part of a long-established trade route, contain more than their share of historic wrecks. As a number of these are Spanish galleons, wrecked on their way to Europe with value cargoes of gold, silver and precious stones, claim to such sites has been the subject of bitter disputes. The results of the legal battles arising from these disputes will have profound implications for the future of underwater antiquities, not only in Florida, but throughout the navigable waters of the United States

Theoretical and Software Considerations for General Dynamic Analysis Using Multilevel Substructured Models

An approach is presented for the dynamic analysis of complex structure sy~t'=!!!S using the finite element method and multilevel substructured models. The fixedinterface method is selected for substructure reduction because of its efficiency, accurac and adaptability to restart and reanalysis. This method is extended to reduction of substructures which are themselves composed of reduced substructures. Emphasis is placed on the implementation and performance of the method in a general purpose software system. Solution algorithms consistent with the chosen data structures are presented in detail. This study demonstrates that successful finite element software requires the use of software executives to supplement the algorithmic language. As modeling and analysis techniques become more complex, proportionally more implementation effort is spent on data and computer resource management. Executive systems are essential tools for these tasks. The complexity of the implementation of restart and reanalysis porcedures also illustrate the need for executive systems to support the non computational aspects of the software. The example problems show that significant computational efficiencies can be achieved through proper use of substructuring and reduction techniques without sacrificing solution accuracy. The unique restart and reanalysis capabilities developed in this study and the flexible procedures for multilevel substructured modeling allow analysts to achieve economical yet accurate analyses of complex structural systems

Spacecraft applications of advanced global positioning system technology

The purpose of this study was to evaluate potential uses of Global Positioning System (GPS) in spacecraft applications in the following areas: attitude control and tracking; structural control; traffic control; and time base definition (synchronization). Each of these functions are addressed. Also addressed are the hardware related issues concerning the application of GPS technology and comparisons are provided with alternative instrumentation methods for specific functions required for an advanced low earth orbit spacecraft

Towards rigorously faking bidirectional model transformations

Bidirectional model transformations (bx) are mechanisms for auto-matically restoring consistency between multiple concurrently modified models. They are, however, challenging to implement; many model transformation languages not supporting them at all. In this paper, we propose an approach for automatically obtaining the consistency guarantees of bx without the complexities of a bx language. First, we show how to “fake” true bidirectionality using pairs of unidirectional transformations and inter-model consistency constraints in Epsilon. Then, we propose to automatically verify that these transformations are consistency preserving — thus indistinguishable from true bx — by defining translations to graph rewrite rules and nested conditions, and leveraging recent proof calculi for graph transformation verification

Evaluating time-lapse borehole gravity for CO2 plume detection at SECARB Cranfield

Bureau of Economic Geolog

Barriers to implementing Sustainable Tourism Policy in Mass Tourism Destinations

The focus of this paper is on identifying the barriers to successful implementation of sustainable tourism policy. The research used exploratory and descriptive approaches to identify barriers from the literature as well as field research to determine perceived barriers from key respondents in two specific locations in the Mediterranean- Malta and Calviá. The research found that although respondents were aware of sustainable tourism, the individual advantage from exploiting shared pooled or shared resources is often perceived as being greater than the potential long-term shared losses that result from the deterioration of such resources, which means that there is little motivation for individual actors (whether governments, elected officials, or individual operators), to invest or engage in protection or conservation for more sustainable tourism

Barriers to implementing Sustainable Tourism Policy in Mass Tourism Destinations

The focus of this paper is on identifying the barriers to successful implementation of sustainable tourism policy. The research used exploratory and descriptive approaches to identify barriers from the literature as well as field research to determine perceived barriers from key respondents in two specific locations in the Mediterranean- Malta and Calviá. The research found that although respondents were aware of sustainable tourism, the individual advantage from exploiting shared pooled or shared resources is often perceived as being greater than the potential long-term shared losses that result from the deterioration of such resources, which means that there is little motivation for individual actors (whether governments, elected officials, or individual operators), to invest or engage in protection or conservation for more sustainable tourism

High-speed Civil Transport Aircraft Emissions

Estimates are given for the emissions from a proposed high speed civil transport (HSCT). This advanced technology supersonic aircraft would fly in the lower stratosphere at a speed of roughly Mach 1.6 to 3.2 (470 to 950 m/sec or 920 to 1850 knots). Because it would fly in the stratosphere at an altitude in the range of 15 to 23 km commensurate with its design speed, its exhaust effluents could perturb the chemical balance in the upper atmosphere. The first step in determining the nature and magnitude of any chemical changes in the atmosphere resulting from these proposed aircraft is to identify and quantify the chemically important species they emit. Relevant earlier work is summarized, dating back to the Climatic Impact Assessment Program of the early 1970s and current propulsion research efforts. Estimates are provided of the chemical composition of an HSCT's exhaust, and these emission indices are presented. Other aircraft emissions that are not due to combustion processes are also summarized; these emissions are found to be much smaller than the exhaust emissions. Future advances in propulsion technology, in experimental measurement techniques, and in understanding upper atmospheric chemistry may affect these estimates of the amounts of trace exhaust species or their relative importance